Microeconomics

Table of Contents

1. Topic pack - Microeconomics - introduction
2. 1.1 Competitive Markets: Demand and Supply
3. 1.1 Competitive Markets: Demand and Supply - notes
4. 1.1 Competitive markets - questions
5. 1.1 Competitive markets - simulations and activities
6. 1.2 Elasticities
7. 1.2 Elasticities - notes
   1. Price elasticity of demand (PED)
   2. PED values
   3. Determinants of price elasticity
   4. Calculating PED
   5. Elasticity along a straight line demand curve
   6. Elasticity and revenue
   7. PED - primary vs manufactured
   8. PED and taxation
   9. Cross elasticity of demand
   10. XED and business decisions
   11. Income elasticity of demand
   12. YED and business decisions
   13. Price elasticity of supply
   14. Possible PES values
   15. PES - calculation
   16. Determinants of PES
   17. PES - primary vs manufactured
8. Section 1.2 Elasticities - questions
9. Section 1.2 Elasticities - simulations and activities
10. 1.3 Government intervention
11. 1.3 Government Intervention - notes
12. 1.3 Government intervention - questions
13. 1.3 Government intervention - simulations and activities
14. 1.4 Market failure
15. 1.4 Market failure - notes
16. Section 1.4 Market failure - questions
17. Section 1.4 Market failure - simulations and activities
18. 1.5 Theory of the firm
19. 1.5 Theory of the firm - notes (HL only)
20. Section 1.5 Theory of the firm - questions
21. Section 1.5 Theory of the firm - simulations and activities
22. Print View

Price elasticity of demand (PED)

PED - formula

Price elasticity of demand is calculated and defined as:

Where Qd = Quantity demanded
and P = Price

The % change in quantity demanded is divided by the % change in price.

Some students find it difficult to remember which way up this equation is. The following 'aide memoire' may be of use. You usually put your dinner (demand) on your plate (price). Demand is over price, D over P!

Price elasticity is negative because price and quantity demanded usually vary inversely with each other. This is so common that the sign is ignored. Do not forget, when price increases, demand falls and vice versa. If necessary, go back and review the section relating to the law of demand.